Mold for casting pistons



March 1 ,'1927. 1,619,135

C. H. KIRBY MOLD FOR CASTING-Hymns O-rginal Filed May 2l, 1923v 2 Sheets-Sheet 2 W////mm v n I f/ l y Patented Mar. 1, 1927. A l j;

UNITED STATES PATENT OFFICE.

(II-IAIIRLIESv I-I. KIRBY, 0F DETROIT, MICHIGAN.

MOLD FOR CASTING PISTONS.

Grignal application led May 21, 1923, Serial No. 640,565. Divided and this application led January 18, 1926. Serial No. 82,144.

' The invention relates to mold fort-he castwith diametrieally opposite cut away p0r- 55 ing ot' pistons and is a divisional of the aptions C, leaving between the same the segplication bearing Serial No. 640,565, tiled mental skirts D. A ring E ot greater thick- May 2l, 1923. ness than the rest. of the blank connects the 5 he invention is particularly applicable segmental skirts D and this ring portion to the casting ot piston blanks ot' such a may be removed after the piston blanks are 60 structure as may be readily machined to machined, thereby forming the two pistons forni pistons 'ot' a special type, wherein the into a structure having freely flexible segskirtis longitudinally slotted forming lexmental skirts, or it may be lett integral with ible segments depending trom an integral the segmental skirts and the blank cut away head portion. centrally of the ring to form pistons in ac- 65 @ne of the objects ot the invention is to lcordanee with my co-pending application `provide a mold for obtaining a hollow blank Serial No. 19,502, tiled March 31, 1925. The closed at the opposite ends and provided interior of the blank A is preferably cast to on the interior with reinforcing ribs for the form ofthe finished piston so that no strengthening` the cast structure. further machining is necessary on the inside 70 Another object is to provide a mold for ot the blank and, for the type'ot piston .distormiiig a single hollow blank `from which closed, it is preferable to provide the reintwo pistons may be obtained. forcing ribs F in the opposite head portions A further object is to provide a mold B and B and the longitudinal extending having a core arranged centrally therewithribs Gr on the segments D. Piston pin bosses 75 i in and supported by core prints extending H are also arranged on opposite sides of the.

into the portion of the mold corresponding ring E.v y to the space betweenthe segmental skirts ot The mold for casting the blank of Figure the piston. l isrpreferably made in two parts, J and J',

A still further obj ect is to provide means each ofwhich has a mold cavity correspond-v 80 for aligning twoV oppositely disposed cores ing toY the outer contour of the blank A. K and for securely supporting the same in represents the core which is arranged within axial alignment at points midway between the cavities in the, moldv and has its outer 3o the ends so that two piston blanks will be surface complementary to the interior struccast as a single structure closed at opposite ture of the piston. The core K is preferably S5 ends. made in two sections K and K2, each being These and other objects are obtained by provided with core prints L and L', extendthe novel construction hereinafter described ing outwardly from the core on Adiam-etand illustrated in the accompanying drawrically opposite sides and supported in the ing, wherein; v upper and lower halves of the mold at points 90 Figure l is a side elevation ot a piston corresponding to the cut away portions C blank shown partly in section. of the blank. It is important that the cores `Figure 2 is a cross section thereof show- K and K2 should be accurately aligned, 4i" ing the interior reinforcing ribs. in order that the walls ot the pistons at Figure 3 is a longitudinal section through opposite ends ofthe blank will be of equal 9- a mold for forming the blank ot Figure 1. thickness and for this purpose a suitable Figure t is a plan view of the mold with interlocking connection M is provided exthe upper halt' removed. Y. tending into the recesses N in the respective Figure 5 is a cross section on the line cores. It is obvious that this connection .55 of Figure 3. f might be made integral with one of the cores 100 Figure 6 illustrates a modified method of it desired, and that the projecting portion aligning the cores. thereof may be cylindrical as shown in Fig- The double piston blank A, shown in Figure 3, or tapering as shown in Figure 6.

ure l is of substantially cylindrical contour From the above description it will be and is closed at opposite ends B and B reapparent that the cores K and K2 are sup- 105 spectively, Vin order to form the heads of ported at their innerv ends and that the portwc separate pistons when'the blank is sevtions forming the interior of the heads of sred into two pieces. The blank is provided the pistons` project inl opposite directions v from the core prints and arenot further supA ported by the outer `mol-d. This arrangement permits of accurately locating the cores with respect to the mold cavity -so as to form the piston walls of uniform thickness, because each of the oppositely projecting'cores serves to balanc-e the other. The i'eature of interlockingthe cores in'aXi/al `alignment is therefor-e of great importance in obtaining castings of uniform thickness. In the particular construction illustrated the vcore prints L on Athe respective cores ifi and Ii? are separated from eachother to provide an annular cavity for the ring E. However, it is to be understood that my invent-ion in certain of my broader aspects is not limited to this particular construction. Thus my invention contemplates broadly the 'torniation ofa mold for a double piston blank Where the'cor is supported intermediate the opposite ends of the piston and has projectingportions extending eppositely into the respective heads.

Vhat I `claim as my invention is:

l. In a mold for casting a piston blank, the combination with an outer mold having a cavity therein corresponding to the outer" contour o'f two oppositely disposed -asiall'y aligned pistons and a core supported in said .outer mold at apoint intermediate its ends,

said cor'e Yprojecting from said Asupport in opposite directions and having its Asurfaces corresponding` to the inner contour of a reinforced hollow piston.

2. In a mold for casting a piston'blank, the combination With an outer mold having a substantially cylindrical cavity therein, a

core axially arranged Wit-hin said cavity and core prints .extending from said cor'e between tlieoppositeends thereof, yandsupported by -said outer mold.

3. In a mold for the formation of two oppositely disposed integral piston castings, the combination of outer mol-d having a mold cavity, a pair of oppositely disposed adjacent cores supported in said outer mold 'and' means toraligning'said cores -in saidmold.

et. In a mold ior the formation of tvvo Oppositely disposed yintegral `piston castings,

the combination o an outer mold4 having a f mold cavity, a pair of oppositely disposed adjacent cores Asdpported in said outer mold and a longitudinal projectionen one of said cores -ei'igagng :a recess in the other core for alignii'ig: said cores in said mold.

5. A mold for piston 'castings' comprising" in and a core arranged Within said cavity.

supported intermediate its' ends by said outer molds, said core having` similar Y portions projecting `in` opposite directions from said support and otherwise disconnected from said outer section, the oppositely projec'ting portions being'conn-ected together to provide a balanced core construction;

In testimony vhe'reotl I vaih; -inyv signature.

CHARLES, H.- Krenn 

